For securing an air bag module in a steering wheel numerous proposals have already been made. When the steering wheels are secured in final assembly by means of a nut screwed to the threaded end of the steering column the air bag module cannot be installed until after the steering wheel has been fitted since it takes up the central portion above the steering wheel hub which needs to remain free for screwing on the nut.
When so-called integrated air bags are to be provided in which the steering wheel is furnished together with the finish-assembled air bag for fitting to the steering column, then some other means of steering wheel fastening is required, for which likewise proposals have already been made, all of which, however, are more awkward to handle than the usual steering wheel fastening by a central nut successfully practiced a million-times over.
In this version--as mentioned--the air bag module cannot be fitted until the steering wheel has been mounted on the steering column and secured thereto.
Then, for securing the air bag module in the steering wheel screw, connectors need to be provided, the access points of which are not provided on the exposed surface of the steering wheel to avoid spoiling optical appeal. Having to insert screws and making the screw connections from the rear of the steering wheel is always a nuisance and time-consuming due to the restricted space availability. Since means of shaving final assembly time in current automotive production are always being sought, screw connectors, especially when needing to be made from the rear of the steering wheel are thus viewed as being a distinct drawback.
This is why attempts have also been made to secure air bag modules to the steering wheel by means of snap-in or clip connectors. However, experience has shown that conventional connectors of this kind fail to be suitable since they are incapable of accommodating the shock forces encountered in air bag activation or because these connectors unlatch when dynamically stressed. Connectors of this type are usually subjected in the locked position to a certain pretension to lock the snap-in or clip connection so that it cannot unlatch under normal conditions. On explosive inflation of an air bag, connectors of this kind are, however, first loaded in the sense of eliminating this pretension, resulting in the latching protuberances no longer being able to reliable clasp when the loading immediately follows in the pretensioning direction.